Gamers hate to wait, especially when facing their imminent virtual demise. When gamers press a button they want an action to occur as soon as possible, with no noticeable delays. Any perceived delays in the actions of the user's avatar are considered unacceptable. Any noticeable delay may be despised, and may be cause for selecting a different gaming system. Gamers also dislike changing the batteries in their handheld controllers. Few experiences are worse for the gamer than being on the cusp of a major victory only to have their controller battery die. Both latency and battery life can be functions of the amount of time and power involved in handling contention and collisions on a communications link between a console and a game controller.
In a conventional wired gaming system, a console may communicate with an accessory (e.g., handheld controller) using a carrier sense media access protocol that includes collision detection (CSMA/CD). The console may be able to exercise some central authority over the accessories to reduce or minimize collisions and thus to reduce or minimize latency between a button press and a corresponding action in a game. However, in a conventional wireless gaming system, the console may communicate with the accessory using a CSMA protocol with collision avoidance (CSMA/CA) instead of CSMA/CD. Communications may require contending for the opportunity to communicate. The contending may increase latency and may produce collisions. The contending may also increase the number of transmissions performed by an accessory, which may negatively affect battery life.
The amount of time and power spent contending for a communication medium may be directly related to the number of devices contending for the medium, or the number, type, or size of messages involved in contending for the medium. Latency and battery life may also be a function of what happens (e.g., handshaking, message passing) after an accessory has won a contention. The number, type, or size of messages involved in communications between the console and the accessory will affect the amount of time that elapses between a user action (e.g., button press, controller re-orientation) and a corresponding game action. The number, type, or size of messages involved in communications between the console and the accessory will also affect how much battery power is used per communication.